Synthetic metal working fluids for ferrous metals

ABSTRACT

A water based mineral oil free metal working fluid contains by weight: 10% triethanolamine; 7% alkylamidocarboxylic acid; 7% ethylenediamine alkoxylate; 4% pentaerythritol alkoxylate; 2% ether carboxylate; 3.5% carboxylic acid; and the remainder chlorine free water.

BACKGROUND OF THE INVENTION

The present invention relates to lubricant fluids used in metal machining. More particularly it refers to a method of preparing a mineral oil free fluid lubricant composition for use in machining ferrous metals.

U.S. Pat. No. 5,132,046 describes metal working compositions containing triethanolamine as a corrosion inhibitor, and pentaerythritol together with carboxylic acid as friction reducing compounds. U.S. Pat. No. 5,431,834 describes the corrosion inhibiting properties of triethanolamine in metal working fluids. U.S. Pat. No. 5,534,172 describes cutting fluids containing triethanolamine and carboxylic acid salt. U.S. Pat. No. 5,721,199 describes mineral oil free aqueous metal working compositions containing triethanolamine. These prior art fluids in many instances have poor water break characteristics resulting in incomplete coating of the substrate by the cutting fluid and the retention of contaminants on the substrate surface following cleaning. Residual water beads are common. The known cutting fluids do not suggest the use of the unique combination of materials in the cutting fluid of the present invention which achieves outstanding performance results when used in machining ferrous metals.

SUMMARY OF THE INVENTION

The present invention describes a synthetic metal working fluid for ferrous metals that is mineral oil free, non-toxic, environmentally friendly, reduces friction between metals and has no disturbing odor. The working fluid contains as active ingredients:

-   -   Triethanolamine;     -   alkylamidocarboxylic acid;     -   ethylenediamine alkoxylate;     -   pentaerythritol alkoxylate;     -   ether carboxylate;     -   carboxylic acid; and     -   water free of chlorine.

DETAILED DESCRIPTION OF THE INVENTION

The prior art describes three different types of metal working fluids; namely, water soluble mineral oils, semi synthetic and synthetic fluids. The present invention is an improved synthetic metal working fluid. The fluid is a blend of six chemical substances in deionized water or water free from chlorine. The blend is formed by first mixing, based on a total weight percent of 100, 15% water, 7-15% triethanolamine (85% concentration) and 4-9% alkylamidocarboxylic acid (Hosfacor 2732). This first mixture is blended with 8% water, 4-9% ethylenediamine alkoxylate, (Genapol PN30), 2-6% pentaerythritol alkoxylate (Genapol PS), 1-4% ether carboxylate (HOSTACOR DTC concentrate) and 2-5% carboxylic acid derivative (HGSTACOR-2125). This second mixture is then blended with 43.5% water. A bactericide (Dodigen 226) and defoamer (Foam Ban HP-710) can optionally be added at less than 1% by weight.

The preferred active ingredients based on weight percent are:

-   -   10% triethanolamine;     -   7% alkylamidocarboxylic acid;     -   7% ethylenediamine alkoxylate;     -   4% pentaerythritol alkoxylate;     -   2% ether carboxylate; and     -   3.5% carboxylic acid.

The balance to make up 100% by weight is chlorine free water.

The mixtures result in a clear liquid of pH 8.4 useful in all computerized cutting machines, including vertical and horizontal drilling and tapping. It also is useful on grinding machines, band saw operations, shaping of steel bars and forming of ferrous metal components. The mixture cannot be used on carbide steel because of carbide leaching.

Generally, the active ingredients are used at a total weight percent in water of 4-6%. The following operations would use the indicated weight percent of active ingredients for optimum results: OPERATION % ACTIVE INGREDIENTS Grinding 2-3%  Cutting 5% Band Saw 3% Drilling 4% Tapping 6% Computer Operated Cutting 3-5% 

The composition does not leave a residue. Therefore, after machining, additional operations such as painting can be done without further cleaning.

The composition provides outstanding lubrication to obtain a smooth cut and also transmits heat from the tool and work piece. The ingredients do not cause dermatitis or give off disturbing odors.

Equivalent ingredients can be substituted for the above ingredients to provide substantially the same function in substantially the same way to achieve substantially the same result. 

1. A water based mineral oil free metal working fluid comprising by weight about: 7-15% triethanolamine; 4-9% alkylamidocarboxylic acid; 4-9% ethylenediamine alkoxylate; 2-6% pentaerythritol alkoxylate; 1-4% ether carboxylate; 2-5% carboxylic acid; and the remainder chlorine free water
 2. A method of producing a water based mineral oil free metal working fluid comprising: (a) a first step of blending 15% by weight chlorine free water with 7-15% by weight triethanolamine and 4-9% by weight of alkylamidocarboxylic acid; (b) a second step of adding 8% by weight chlorine free water to the step (a) blend; (c) a third step of adding 4-9% by weight ethylenediamine alkoxylate, 2-6% by weight pentaerythritol alkoxylate, 1-4% by weight ether carboxylate, and 2-5% carboxylic acid to the step (b) blend; and (d) adding to the step (c) blend sufficient chlorine free water to produce a 100% by weight blend.
 3. The method of producing a water based mineral oil free metal working fluid according to claim 2, wherein an additional step (d) about 0.01 to 1 volume percent of a biocide is added to step (c) blend.
 4. The method of producing a water based mineral oil free metal working fluid according to claim 3, wherein an additional step (e) about 1% by volume of defoaming agent is added to the step (d) blend.
 5. A water based mineral oil free metal working fluid comprising by weight about: 10% triethanolamine; 7% alkylamidocarboxylic acid; 7% ethylenediamine alkoxylate; 4% pentaerythritol alkoxylate; 2% ether carboxylate; 3.5% carboxylic acid; and the remainder chlorine free water. 